KVM: arm64: Use fallback mapping sizes for contiguous huge page sizes (2f40c460) · Commits · 戴 / test

Although huge pages can be created out of multiple contiguous PMDs or PTEs, the corresponding sizes are not supported at Stage-2 yet. Instead of failing the mapping, fall back to the nearer supported mapping size (CONT_PMD to PMD and CONT_PTE to PTE respectively). Suggested-by:

Marc Zyngier <maz@kernel.org> Signed-off-by:

Gavin Shan <gshan@redhat.com> [maz: rewritten commit message] Signed-off-by:

Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201025230626.18501-1-gshan@redhat.com

arch/arm64/kvm/mmu.c

+19 −7

Original line number	Diff line number	Diff line
		@@ -787,14 +787,26 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
		vma_shift = PAGE_SHIFT;
		}

		if (vma_shift == PUD_SHIFT &&
		!fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
		switch (vma_shift) {
		case PUD_SHIFT:
		if (fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
		break;
		fallthrough;
		case CONT_PMD_SHIFT:
		vma_shift = PMD_SHIFT;

		if (vma_shift == PMD_SHIFT &&
		!fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) {
		force_pte = true;
		fallthrough;
		case PMD_SHIFT:
		if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE))
		break;
		fallthrough;
		case CONT_PTE_SHIFT:
		vma_shift = PAGE_SHIFT;
		force_pte = true;
		fallthrough;
		case PAGE_SHIFT:
		break;
		default:
		WARN_ONCE(1, "Unknown vma_shift %d", vma_shift);
		}

		vma_pagesize = 1UL << vma_shift;

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